I70 has congestion about twice a week in the winter – masses going to and from ski towns, and is generally fine the rest of the year. It also has grades and curves that high speed trains couldn’t handle. Denver is about a mile above sea level. I70 through the eisenhower tunnel is more than 11000 feet about sea level, the highest vehicular tunnel in north america. The road has long stretches with greater than 7% grade. Tunneling through the mountains with a gentle grade and wide curves to allow high speed rail would be an engineering challenge, and cost a fortune. The ten billion mentioned in that article is overly optimistic. The distance and traffic involved can’t justify the cost.